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Biomedical subjects

T M Radda

Publications and source records attributed to T M Radda.

At least 19 recordsLinked to original sources

Reversible changes of visual acuity and pattern-electroretinograms after blue-green argon laser photocoagulation of diabetic patients.

Visual acuity, color vision, pattern-visual-evoked-potentials (P-VEPs) and pattern-electroretinograms (P-ERGs) were measured in 13 diabetic subjects before, and 24 hours and 5 weeks after blue-green argon laser treatment. As control, the same examinations were performed in 7 normal subjects and 7 diabetic patients before and after slit lamp examination with the Goldman three mirror contact lens. Visual acuity and P-ERG amplitudes were significantly reduced one day after the laser treatment, while 5 weeks after the laser coagulation, visual acuity and P-ERG amplitudes recovered to pretreatment values. The control group showed no significant changes after slit lamp examination. Since fluorescein angiography revealed no macular changes after laser treatment, the possibility of a reversible functional light damage after blue-green argon laser coagulation (ALC) is discussed.

Aged

[Non-freeze epikeratoplasty in recurrent pterygium].

We present five patients with recurrent pterygium. Prior to our surgical procedure the patients had had several surgical interventions as well as radiotherapy. Up to four-fifths of their corneal surface was covered by a multilayered pterygium including symblepharon scarring in the lower and upper lid, completely immobilizing the globe. The pterygium was removed, the conjunctival strains excised, and corneal abrasion was carried out with a rotating diamond tool. Finally, an optical non-freeze epikeratoplasty processed by the Non-freeze Barraquer-Krumreich-Swinger refractive set (BKS-1000) was sewn on the recipient cornea with a double running antitorque suture. In all patients, the epikeratoplasty donor cornea remained clear. In one patient there was a small pterygium recurrence, which was treated successfully with 5-fluorouracil.

Adult

[Temporary silicone oil implantation following vitrectomy in proliferative diabetic retinopathy].

Report on 23 patients with proliferative diabetic retinopathy who underwent silicone oil implantation due to recurrent intravitreal hemorrhages following pars plana vitrectomy. Postoperatively, it was possible to perform panretinal laser photocoagulation without difficulty or haste. After an average period of 4 months, silicone oil was removed from 10 eyes. Subsequent hemorrhages in 4 of these eyes are due to diabetic retinopathy, not to silicone oil. In 6 cases, silicone oil removal is planned for the near future; in a further 7 cases, silicone oil removal has been postponed because of the potential danger of further traction retinal detachment.

Diabetic Retinopathy

[Angiotensin-converting enzyme in patients with temporal arteritis].

It is well documented in the literature that patients with active sarcoidosis exhibit elevated serum ACE activity. Since both temporal arteritis and sarcoidosis represent granulomatous inflammatory conditions, this study was undertaken to determine serum ACE activity in patients with temporal arteritis as well as in a control group. The serum ACE levels in patients with temporal arteritis were significantly lower than in the controls. Hence, granulomatous inflammation in temporal arteritis seems to differ radically from the granulomatous inflammation present in sarcoidosis. Serum ACE activity was increasing during cortisone treatment of patients with temporal arteritis, but dropped again as soon as cortisone therapy was discontinued.

Aged

[Use of neodym-YAG-lasers in ophthalmology].

Structures within the eye bulb diminishing visual acuity can be cut by means of neodymium-YAG-laser without surgical opening of the globe. The First Eye Department has had the first instrument of this kind in Vienna at its disposal since the summer of 1984. Up to now it has been used for posterior capsulotomy, iridotomy, opening pupillary membranes and for cutting vitreous membranes in 84 operations altogether. The advantages of neodymium-YAG-laser are minimal psychological and physical stress for the patient and the possibility of out-patient surgery. A possible transient increase in the eye pressure and endothelial cell loss are disadvantages. Our experiences with the Lasertek Neodymium-YAG-laser model 135 are reported.

Cataract Extraction

[Immunosuppressive therapy with cyclosporin A following penetrating keratoplasty].

Report on 11 patients who underwent penetrating keratoplasty and were treated with Cyclosporin A for an average of 6 months because of excessive superficial and deep vascularization of the recipient cornea. In none of the patients was a permanent Cyclosporin A-induced side-effect observed. After an average follow-up period of 11 months 9 grafts remained completely clear; however, an allograft-reaction occurred in 2 cases in spite of the immunosuppressive therapy.

Corneal Diseases

[Use of the neodymium YAG laser following posterior chamber lens implantation].

The authors report on the neodymium-YAG laser used after extracapsular cataract extraction with the implantation of a posterior chamber lens in 1726 patients. The most common indication was capsular fibrosis necessitating posterior capsulotomy. The alternative to the YAG laser would be a bulbus-opening procedure via pars plana using a Sato knife. The advantage of the YAG laser in comparison with capsulotomy with a Sato knife is that there is no danger of intraocular infection or bleeding (which may result from tension on the fibers with the first method). A disadvantage of the YAG laser method is a possible transitory increase in intraocular pressure and an endothelial cell loss. In 1726 cases with posterior chamber lenses 45 capsulotomies using the YAG laser were necessary. A further indication for the YAG laser are posterior chamber lenses decentered by capsular fibrosis (3 cases). A third indication is chorepraxia after posterior chamber lens implantation. In three cases with posterior chamber lenses a flattening of the pupil occurred because remnants of the anterior capsule had shifted into the anterior chamber. In two cases a pupil became decentered for no apparent reason. In these cases YAG laser therapy is indicated. In at least three cases pupillary membranes were cut with the YAG laser. The authors treated their patients with the Lasertec model 135 YAG laser (Q-switched mode).

Humans

Fosfomycin levels in human aqueous humor after intravenous administration.

Following intravenous infusion of an 8 g single dose of the antibiotic agent fosfomycin, its penetration into human primary aqueous humor was investigated. 1-2 h after the start of infusion, peak values of 35 to 60 micrograms/ml were reached. These concentrations in the aqueous humor would inhibit a high percentage of gram-positive and gram-negative strains commonly causing bacterial endophthalmitis. The infusion of an 8 g dose of fosfomycin immediately preceding intraocular surgery thus constitutes effective peri-operative prophylaxis. Moreover, as a broad-spectrum antibiotic, fosfomycin is indicated as initial therapy in intraocular bacterial infections.

Aged

[Electron microscopic and immunohistologic studies of patients with Horton's temporal arteritis].

Temporal arteritis is a systmic disease with a predilecation for the cranio-temporal vascular area. Histologically it is a panarteritis. Diagnosis is based on the presence of lymphocytes, histiocytes and foci of epitheloid cells in the media of the temporal artery. The presence of giant cells is, however not obligatory. The present study emphasizes the value of biopsy of the temporal artery in diagnosing this disease. It, furthermore, also points out the 10-percent possibility of false negative biopsy results based on patchy vascular lesions. Tenderness to touch of the temporal artery, characteristic of temporal arteriitis, can be explained by perineural inflammatory infiltration of nerves in the adventitia of this artery. Examination under the electron microscope reveals almost complete destruction of the smooth muscles of the media by epitheloid cell granulomas. Massive neogenesis of collagen ensues. Furthermore, numerous myofibroblasts, macrophages and histiocytes are observed. Several macrophages close to each other create the impression of giant cells in the light microscope. The electron microscope image allows for clear differentiation between temporal arteritis on one hand and of arteriosclerosis on the other. Using the immunoperoxidase method in temporal arteritis, immune globulines are found intracellularly in plasma cells. Extracellularly, however, neither immune golbulins nor complement deposits are found in the vascular wall. Thus, the assumption that temporal arteritis represents a immune complex disorder cannot be maintained. The most frequent ophthalmologic complication in temporal arteritis is ischemic optic neuropathy. Histologic examination of a bulbus presenting anterior ischemic optic neuropathy in a case of temporal arteritis revealed predominantly lymphocytic infiltrations of the short and long ciliary arteries. No inflammatory infiltration was found in the central retinal artery. The development of anterior ischemic optic neuropathy can be explained by impaired perfusion or by occlusion of the short posterior ciliary arteries. In 60% of patients suffering from temporal arteritis, we found anticollagen antibodies in the serum. Collagenization of the vascular wall as observed in our electron-microscopic examinations must, therefore, be considered the paradoxical consequence of an immune reaction caused by collagen auto-antibodies. Collagen auto-antibodies play a decisive role in the maintenance and chronicity of the inflammatory process in temporal arteritis. In therapy, corticosteroids should not be administered according to rule but rather in doses adjusted to individual requirements.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged

[Intraocular penetration of netilmicin].

The penetration of netilmicin, a semisynthetic aminoglycosid into the primary human aqueous humor was determined. The antibacterial spectrum of netilmicin is adequate to gentamicin. The efficacy also covers gentamicin resistant strains. After intramuscular injection of 5 mg/kg body weight aqueous levels higher than the minimum inhibitory concentration (MIC) of staphylococcus aureus, Escherichia coli, Klebsiella, Enterobacter, Citrobacter and Proteus morganii were obtained. In the therapy of bacterial endophthalmitis the synergistic effect of netilmicin with beta-Lactam antibiotics in the form of a combined therapy should be made use of. For perioperative prophylaxis the newer aminoglycosids are not indicated because there is the danger of a development of resistant strains.

Aged

Secondary corneal amyloidosis: clinical and pathohistological examinations.

A patient suffering from an excentric vascularized tumorlike corneal change is reported who submitted to a penetrating optic keratoplasty. The diagnosis of a secondary corneal amyloidosis was established by histological examination. The clinical course and pathological findings by means of light- and electron microscopy are described and discussed.

Adult

[Immunofluorescence studies of the human trabecular meshwork].

Accumulation of extracellular material in the trabecular meshwork is responsible for increased resistance to outflow in the human eye. By means of the indirect immunofluorescence technique the authors detected extracellular collagen type IV, fibronectin and laminin in the trabecular meshwork and the wall of Schlemm's canal of glaucoma patients and controls. Collagen type IV is the so-called "basement membrane collagen" present in the lens capsule, Bowman's and Descemet's membranes. Fibronectin is a glycoprotein with many biologic activities; it can promote cell attachment and forms complexes with collagen. Laminin was isolated in 1979 and is present in the lamina lucida of basement membranes. The increased production and pathological metabolism of these three substances might be of some importance in the pathogenesis of primary open-angle glaucoma.

Collagen

[Erythroprosopalgia or cluster headache].

Erythroprosopalgia is characterized by severe unilaterally and periodically occurring attacks of headache. During these fits of pain there is an increase in blood flow in the homolateral eye, conjunctival injection and epiphora. Males aged between twenty and forty are most frequently affected. The clinical picture, therapy and differential diagnosis of this disease are discussed.

Adult

[Healon as an internal tamponade in retinal detachment surgery].

In 14 selected cases of retinal detachment the vitreous cavity was filled with Healon (0.8-4.0 ml) during subretinal drainage. Follow-up periods ranged between 2 and 7 months. In 12 cases the retinal detachment was cured; in 2 eyes redetachment with massive periretinal proliferation occurred. In addition to transient Tyndall phenomena, which were frequently seen in the anterior chamber and vitreous cavity, the intraocular pressure increased to as much as 45 mm Hg postoperatively in 5 cases. Owing to failure of the antiglaucoma therapy in 3 cases the Healon filling had to be removed.

Aphakia, Postcataract